GPS Anti Spoof

36 reviews
Content rating
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About this app

Sextant required! Instant celestial navigation... The most reliable way to detect GPS Spoofing and other anomalies of electronic navigation is by comparing against the measured altitudes of celestial bodies including the Sun, Moon, bright planets and stars. This app calculates the exact altitude that should be observed with a sextant assuming that the GPS position is correct. No paperwork is required, no tables of corrections. All corrections are included automatically: index error, system time error, dip of the horizon, refraction, temperature and pressure corrections to refraction, altitude above sea level, parallax, and also gravitational deflection of the vertical (a correction of up 2 nautical miles not handled by any other celestial navigation sight-clearing product) are all included automatically. It's also a great sextant trainer: take a sight and immediately compare against the app's display. The app works off-network. If a network connection is available, it can download temperature and pressure information automatically. The ephemeris data is generated from the same JPL numerical integrations of lunar and planetary motions used by the official Nautical Almanac and Astronomical Almanac. All coordinates are accurate to one second of arc, and displayed sextant altitudes are accurate to better than a tenth of a minute of arc (the limiting precision of the best marine sextants).
Updated on
May 23, 2024

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
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No data collected
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Data is encrypted in transit
Data can’t be deleted

Ratings and reviews

33 reviews
Alastair Stewart
June 7, 2022
Excellent tool for practicing Celestial Navigators! I like to use it when taking actual sights with my sextant, the pause feature makes it very simple for an assistant to accurately freeze and record the time of your fix when you call "Mark!"
1 person found this review helpful
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Cristian Calin
May 19, 2021
Great app. Unfortunatelly can use only the imperial system for height, temperature and pressure. Edit: after the latest update, the metric system was implemented. I appreciate your work! I would like to buy you a beer, but unfortunately I find the Pro version too expensive to justify it, for the amount of time I'm using the app. Any other way I can do it?
2 people found this review helpful
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Clockwork Mapping
May 10, 2021
Be sure to update! Recent versions, of course, include SI "metric" units. :)
A Google user
July 20, 2019
Awesome app. A must for both seasoned and aspiring celestial navigators.
6 people found this review helpful